I’m running windows 7 here, 4.12 Preview 3 compiled from source (with SDK already installed) with a GeForce GT 750M. Normal editor runs fine, and I can preview in PIE mode. I crash when adding the - flag. Stack is too big for the comment, so I attached a text file. Top error is:
Fatal error: [File:C:\UnrealEngine-4.12.0-preview-3\Engine\Source\Runtime\VulkanRHI\Private\VulkanUtil.cpp] [Line: 444]
vkCreateSwapchainKHR(Device.GetInstanceHandle(), &SwapChainInfo, nullptr, &SwapChain) failed, VkResult=-1000011001
at C:\UnrealEngine-4.12.0-preview-3\Engine\Source\Runtime\VulkanRHI\Private\VulkanSwapChain.cpp:191
with error VK_ERROR_VALIDATION_FAILED_EXT